Upper Eocene volcanic rocks (WAEOv1a;0)

State	Washington
Name	Upper Eocene volcanic rocks
Geologic age	Late Eocene
Original map label	Ev1a
Comments	The Northcraft formation is 680-1400 ft thick (Snavely and others, 1958).
Primary rock type	andesite
Secondary rock type	basalt
Other rock types	conglomerate; sandstone; siltstone; mudstone; welded tuff
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow) Igneous > Volcanic > Mafic-volcanic > Andesite (Flow) Minor Igneous > Volcanic > Mafic-volcanic > Basalt (Flow) Igneous > Volcanic > Mafic-volcanic > Andesite (Volcaniclastic, volcanic breccia) Incidental Sedimentary > Clastic > Siltstone (Tuffaceous) Sedimentary > Clastic > Mudstone (Tuffaceous) Sedimentary > Clastic > Sandstone (Tuffaceous) Sedimentary > Clastic > Conglomerate (Bed) Igneous > Volcanic > Mafic-volcanic > Basalt (Volcaniclastic, volcanic breccia) Igneous > Volcanic > Mafic-volcanic > Basalt (Pyroclastic) Igneous > Volcanic > Mafic-volcanic > Andesite (Pyroclastic)
Map references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.
Unit references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000. Walsh, T. J., Korosec, M. A., Phillips, W. M., Logan, R. T., Schasse, H. W., 1987, Geologic Map of Washington-Southwest Quadrant: Washington Division of Geology and Earth Resources, Geologic Map GM-34, scale 1:250,000. Luedke, Robert G., 1998, Maps showing distribution, composition, and age of Early and Middle Cenozoic volcanic centers in Oregon and Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-2291-D, scale 1:1,000,000. [http://pubs.er.usgs.gov/publication/i2291D] Roberts, A. E., 1958, Geology and Coal Resources of the Toledo-Castle Rock District, Cowlitz and Lewis Counties, Washington: U. S. Geological Survey Bulletin 1062, 71 p, 6 pls. [http://pubs.er.usgs.gov/publication/b1062] Snavely, P. D., Jr., Brown, R. D., Roberts, A. E., Rau, W. W., 1958, Geology and Coal Resources of the Centralia-Chelalis District, Washington: U. S. Geological Survey Bulletin 1053, 149 p. [http://pubs.er.usgs.gov/publication/b1053]
Geographic coverage	King - Lewis - Pierce - Thurston